1. Field of the Invention
The invention relates to a beverage preparation machine comprising at least one pinch valve in the fluid line system.
The invention relates in particular to a beverage preparation machine of the above-mentioned type, thus for example to a coffee or espresso machine, where a liquid or fluid component must be redirected to different outlets or which is also particularly suitable for preparing beverages comprising two different liquid components, such as, e.g., latte.
2. Description of Related Art
There are thus models of espresso machines, where the dispensing of coffee or cappuccino is executed via two different outlets in each case at different dispensing locations. A change-over of the dispensing path for coffee is required here.
In the case of the preparation of latte, the two liquid components are coffee and milk, which are in each case fed to a single or also to different outlets from different sources or containers. A change-over on the side of the feed line or delivery line is required here.
For this purpose, switching components comprising suitable valve and/or control functions must be present in the fluid line system of the beverage preparation machine.
The term “valve and/or control function” will be used hereinbelow with the following meaning:                Valve function is understood to be a function, in response to which a fluid passage is turned on, off or changed over.        Control function is understood to be a function, in response to which a fluid throughput quantity is reduced or increased in a controlled manner, which can obviously also include valve functions.        
Known switching components in beverage preparation machines are the very frequently used magnetic valves. Magnetic valves, however, have a number of disadvantages, which are possibly undesirable. They are heavy and expensive, typically also relatively susceptible to being soiled and must furthermore be energized constantly in at least one activation position, which then also leads to an increasing heating of the electromagnets.
Pinch valves per se are also known. In some cases, they are preferred because of the much smaller susceptibility to being soiled, because the fluid medium guided in a pinchable valve does not have any contact to the valve mechanics. They are thus also suitable for the most different of fluid media and in particular also for controlling flow rates.